شركات التداول في الامارات Lake Toba is a large lake, 100 km long and 30 km wide, in the middle of the northern part of the Indonesian island of Sumatra. Lake Toba – the largest lake in all of Southeast Asia – is situated in the caldera of the huge Toba volcano, which erupted about 100,000 years ago. Many scientists believe that this eruption triggered the last ice age. The Toba eruption is dated at 73,000 ± 4000 years ago. It had a Volcanic Explosivity Index of 8, making it the most recent supervolcano-sized and probably the largest volcanic eruption within the last two million years. The eruption probably lasted two weeks until it naturally caused a great collapse and formed the caldera, which filled with water creating Lake Toba.

كيف يتم التداول في بورصة الذهب دبي A large area collapsed after the ejection of so much subsurface material, forming a caldera, which filled with water creating Lake Toba. Later, the floor of the caldera uplifted to form Samosir, a large island in the lake. Such uplifts are common in very large calderas, apparently due to the upward pressure of unerupted magma. Toba is probably the largest resurgent caldera on Earth.

سعر الذهب في الامارات Smaller eruptions have occurred at Toba since. The small cone of Pusukbukit has formed on the southwestern margin of the caldera and lava domes. The most recent eruption may have been at Tandukbenua on the northwestern caldera edge since the lack of vegetation could be due to an eruption within the last few hundred years. In addition some parts of the caldera have experienced uplift due to partial refilling of the magma chamber, for example pushing Samosir Island and the Uluan Peninsula above the surface of the lake. The lake sediments on Samosir Island show that it has been uplifted by at least 450 metres since the cataclysmic eruption.